Fuel-injecting device for internal-combustion engines



Dec. 30, 1930. K. J. E. HESSELMAN 8 ,8

FUEL INJECTING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed Nov. 22. 1926 2 Sheets-Sheet l Dec. 30, 1930.. K. J. E. HESSELMAN FUEL INJECTING DEVICE FOR INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet 2 Filed Nov. 22, 1926 Patented Dec. 30, 1930 UhllTED STATES KNUT JONAS ELIAS HESS ELMAN, OF SALTSJ'O-STORANGEN,.SWEDEN FUEL-INJECTING DEVICE FOR INTERNAL-COMBUSTIGN ENGINES Application filed November 22, 1926, Serial No. 149,970, and in Sweden December 4, 1925.

The present invention relates to internal combustion engines for liquid fuel which is injected without the aid of air under pressure under the control of a valve opened auqtomatically by the pressure of the fuel supplied. To control such valves it has been already proposed to use a single diaphragm subjected to the pressure of the fuel which may or may not at the same time be spring to controlled.

Due to the high injecting pressure of the fuel the movements of the diaphragm of such a valve mechanism and thus also the valve lift will be exceedingly small even in the case of very high strains on the material, that is,

when using material of the highest quality available. In fact,.said movements will only amount to a few hundredths of a millimeter.

It is thus evident that the work of the valve 2% needle and the opening pressure of the valve will be highly affected even by a very small wear of the valve seat. This is particularly true in case of modern designs in which very high pressures are used in injecting the fuel, 5 as, for instance, pressure of 300 atm. to open the fuel valve.

The object of the invention is to provide a diaphragm controlled valve of the said type which may be easily adjusted when desired so and is simple to manufacture.

One feature of the invention involves that the valve seat proper and the contact surfaces to receive and clamp the diaphragm are all situated in the same plane, the liquid pressure on the diaphragm being balanced by a spring and the diameter of the valve seat being large as compared with the outer diameter of the resilient portion of the diaphragm.

In the drawing some embodiments of the invention are shown. Fig. 1' is a longitudinal section of a complete fuel injecting device.- Figs. 2, 3, 4 are longitudinal sections of parts of different embodiments. Fig. 5 shows a detail of the device shown in Fig. 1. Fig. 6 is a' diagrammatic view of a further embodiment with certain parts in section.

With reference to Fig. 1 the numeral 1 indicates the valve casing which is adapted to be inserted into the wall of the combustion chamber of air-internal combustion engine.

Said valve casing is formed with a passage 2 for the supply of liquid fuel under pressure as well as with a discharge passage 3 at the end of which facing the engine the nozale 4 is provided. Inserted within the valve casing is a valve seat 5 of some appropriate hard material. The valve seat proper comprises the fiat ground upper edge of an annular collar 6 surrounding the upper opening of the passage 3. The valve casing 1 extends upwardly as a collar 7 preferably concentric relatively to the collar 6 and having its top edge lying in the same plane as the top edge of the collar 6. The fuel supplying passage 2 leads to the annular chamber 8 formed between the collars 6 and 7 Resting on the upper edges of the collars 6 and 7 is the diaphragm. The diaphragm comprises a single piece, preferably, of steel of the highest strength and hardness. The shape of the diaphragm used in connection with the embodiment shown in Fig. 1 is more clearly illustrated in Fig. 5, Where the diaphragm is shown separately.

The diaphragm comprises an inner, comparatively thick disk 9 adapted to engage the valve seat 6, a strong ring 10 concentric to the disk 9, which is adapted to be clamped to the top of the collar 7 a comparatively thin annular disk 11 situated above the space between said tWo first-mentioned members, and thin cylindric walls 12 and 13 connecting the disk 11 to the central portion 9 and the ring 10, respectively. silient portion proper of the diaphragm. The walls 12, 13 are made so thin as not to hold the disk firmly clamped at its edges but allowing comparatively free movements thereof due to its elasticity.

To ide the diaphragm relatively to the collar at the insertion of the diaphragm a ring 14: is placed around the diaphragm and the uppermost portion of the collar 7 which is of the same diameter as the diaphragm. The circumferential portion of the diaphragm is clamped against the edge of the collar 7 by a shell or cap 15 threaded on the upper end of the body 1, and closed at its top by a removable cover as shown. Engaging the internally threaded upper end of the The disk 11 forms the reshell or cap 15 is a threaded block 17. Said block serves as an adjusting screw for a spring 16 enclosed in the shell or cap 15 which is adapted to exert a pressure upon the diaphragm. The spring 16 does not act directly upon the diaphragm but acts on the disk shaped head 18 of a bolt 19 depending into the central depression of the diaphragm so as to engage the central disk thereof.

By means of the screw 17 the lifting pressure of the diaphragm and thus also that of the valve may be varied. To prevent any considerable increase of the fuel pressure, due, for instance, to stopping of an aperture of the nozzle 4, from lifting the diaphragm in too high a degree so as to overstrain the material an adjustable stop 20 may be provided at a suitable distance above the diaphragm portion 11.

Engaging into the annular space between the diaphragm walls 12 and 13 is a member 21 preferably carried by the filling piece 5 Which forms between itself and the diaphragm portion 13, 11, 12, a comparatively narrow fuel passage which extends upwardly fromthe fuel inlet 2 and then downwardly to the valve seat. This will prevent accumulation of air below the diaphragm disk 11. The liquid under pressure entering through said passage will lift, when the pressure becomes sufiiciently high, the diaphragm disk 11 which lifts in turn the central diaphragm portion 9 so as to allow the fuel to enter the outlet passage 8. When the valve opens a pressure above atmospheric will be produced Within passage 3 and nozzle 4. Said pres sure will give rise to an upwardly directed power acting on the lower surface of the valve, that is, on the area inside the edge 6, and said power will increase with increasing pressure. It is to be noted that it is substantially this power that determines the degree of valve lift. passage of the valve may be sufiicient the valve diameter must be chosen large as compared with the outer diameter of the resillent portion of the diaphragm. In fact, a valve diameter equal to about A; of the outer diameter is concerned.

It is of importance that the fairly thick ring 10 is provided on the diaphragm. This is due to the fact that uniformly thick diaphragms clamped between two rings, that 18, in the present case between the valve casing 1 and the cap 15., are of very different flexibility, according as the pressure of clamping is high or low and due also to the character of the surfaces between which the diaphragm is clamped. By the arrangement described, that is, the provision of the strong ring 10, the flexibility of the diaphragm will be independent of the pressure of clamping and the character of the surfaces.

Due to the fact that the top edges of the collars 6 and 7, that is, the valve seat and In order that the section of the clamping surface of the collar, are exactly in the same plane and the lower surfaces of the diaphragm portions 9, 10 are, likewise, exactly in the same plane the necessary, substantially mathematically exact contact may be readily obtained and, furthermore, any necessary adjustments after wear or damage of said surfaces may be readily made by means of a surface plate and any appropriate grinding means.

Fig. 2 illustrates a simplified design of the diaphragm. The diaphragm comprises in this case a disk 22?), 22c exactly plane on its lower surface and having in its upper surface both an annular recess 22 to produce the elastic portion 23, and a central recess to receive the bolt 19 transmitting the pressure of the spring 16 to the diaphragm.

Fig. 3 shows a diaphragm 30 having a removable central portion 31 to engage the seat 6 in case it should be desired to manufacture same from any material other than that used for the remainder of the diaphragm. The portion 31, the lower side of which lies in the same plane as the lower surface of the clamping portion 32 of the diaphragm engages by a threaded extension an opening of the diaphragm and is held in place by means of a threaded cap 33 upon which the bolt 19 of the spring 16 rests.

In certain cases it may be desirable to obtain an exceedingly thin and flexible diaphragm. Fig. 4 shows a design satisfying this condition. The thin annular diaphragm disk 40 is formed integral with the central portion 41 and the thick outer clamping ring 42. Acting on the portion 41 is a comparatively thin spring 43 while a stronger spring 44 through the intermedium of a ring 45 acts on the thin diaphragm disk 40. The fuel pressure reaches the lower side of the portion 40 through grooves 46 in the top surface of the valve casing 1.

With the valve open part of the spring pressure (that is, that of spring 44) acts directly upon the flexible portion of the diaphragm whereas, with the valve closed, said part of the spring pressure will be taken up by a collar 47 between the grooves 46 which extends up to the valve seat plane.

It is to be noted that in all of the embodiments above described the guidingmember 14 may be formed integral with the ca 15.

In the embodiment shown in ig. 6 the spring pressure acting on the diaphragm is dispensed with and instead thereof I make use of a fluid pressure distributed over the entire diaphragm surface.

In Fig. 6, the reference numeral 1 indicates the valve casing having its fuel inlet passage at 2 and its fuel outlet at 3 terminated by a nozzle at 4. Placed in a recess formed in the top edge of the valve casing 1 is avalve seat body 5 of hard material the evenly ground top surface 6 of which forms the limit the upward movement of the diaphragm The diaphragm 11 and the disk are clamped between the surface 7 and an inner shoulder formed in a cap or receptacle, 15 preferably screwed down upon the valve casing 1. Said receptacle 15 is adapted to be filled with a liquid or a substance of a character like that of a liquid. 1

The receptacle 15 is connected by a pipe 51 to a pressure equalizing device 52. By means of a pump 53 the receptacle 15 and the pressure equalizer 52 may be put under pressure the value of which may be determined by a manometer 5d.

In the drawing the fuel supplying pump is shown at 55 By means of a discharge pipe said pump communicates with the supply-passage 2. The pipe 57 represents the suction conduit of the pump.

When fuel is supplied to the under side of the diaphragm by means of the pump 55 the diaphragm will be lifted so as to open the valve at a pressure lying above that existing on the upper side of the diaphragm, said first-mentioned or lifting pressure being further determined by the diameter of the valve seat as compared with the outer diameter of the diaphragm.

It may be essential to take steps to prevent the fuel pump from supplying oil to the fuel valve, when the diaphragm is not subjected to a sufficiently high liquid pressure on its upper side (due, for instance, to the operator neglecting to pump oil or to a pipe breakage) At the lower portion of the drawing a device is shown to prevent starting of the engine should the pressure on the upper side'of the diaphragm not reach a certain value, or to stop the engine should the pressure fall below such a value.

To this end means is provided to maintain the suction valve of the pump 55 open at such instances. The suction valve, indicated at 58 in the drawing, is controlled by the pump plunger 61 through the intermedium of a rocking lever 59 and a bell crank lever 60 so as to be opened when the plunger has passed the quantity of oil determined in order to permit any excess of oil to return to the section pipe.

The arm of the rocking lever facing the suction valve is engaged by a pawl 62 mounted at 63 and controlled by a manometer spring =64 secured to the box 65-the interior of which is subjected to the pressure existing in the receptacle 15 transmitted by the pipe 66.

Should this pressure decrease'the spring 64 y will change its shape moving the pawl to the dotted position so as to maintain the suction valve in open state thereby preventing the fuel pump from passing any oil to the pipe 56. The arrangement described may, of course, be modified in several ways.

The pressure equalizer 52 is not essential and may be dispensed with in which case the entire resilient liquid volume may be contained within the receptacle 15 which may also contain the pump 53 or a mereplunger which, when moved into the receptacle, will decrease the inner volume thereof accordingly to thereby adjust the pressure therein to the value desired.

It is to be noted that the invention may also be modified in various other ways with out departing from the principle of the invention.

In connection with engines having a plurality of fuel valves said valves may preferably be connected to a common pressure equalizer to be operated simultaneously to the opening pressure desired which bears a certain, readily determined relation to the loading pressure as indicated on the manometer.

Furthermore, the opening pressure may be readily varied with the engine running according as the load varies or according to the character of the oil or other conditions.

If desired, the liquid pressure load on the diaphragms as set forth in connection with Fig. 6 may be combinedwith a spring pressure load'as set forth in connection with Figs. 1-5.

It is further to be noted that any elastic pressure medium may be used instead of fluid, as above described,,provided it may be capable of exerting the necessary pressure on the diaphragm.

,What I claim is 1. In a device for injecting liquid fuel under pressure into internal combustion engines, a valve casing, a plane valve seat, a surface in the same plane as said seat, a valve body to engage said seat, a pressure operated diaphra'gm formed integral with said valve body to control same, said diaphragm having a non-elastic circumferential portion clamped to said surface, and a stop disk clamped to a rigid circumferential portion in the plane of diaphragm therebetween, and means to exert the valve to be clamped against said sura pressure on said body in the direction torounding surface, and means to produce a wards said valve seat.

In testimony whereof I have slgned my pressure acting on said diaphragm to hold said central portion in engagement with said valve seat, said pressure being adapted to be overcome by the pressure of the liquid fuel to open the valve.

3. In a device for injecting liquid fuel under pressure into internal combustion engines, the combination of a valve casing, a plane valve seat surrounding an annular liquid outlet channel in said casing, a liquid inlet channel outside said seat and an annular surface surthe valve and means to urge the valve to its seat.

4. In a device for injecting liquid fuel under pressure into internal combustion engines, the combination of a valve casing having a plane valve seat, and a concentric valve clamping face in the plane of the seat; with a diaphragm valve having a thickened portion cooperating with the seat and a thickened marginal portion fitting on said face, a ring closely fitting the periphery of said marginal portion and face and covering the joint between them, and a spring-urged valve seatin device having universal contact with the va ve.

5. In a device for injecting liquid fuel under pressure into internal combustion engines, the combination of a valve casing having a plane valve seat and a concentric valve clamping face in the plane of the seat; with a diaphragm valve having a thickened portion cooperating with the seat and a thickened marginal portion fitting on said face, a ring closely fitting the periphery of said marginal portion and face and covering the joint between them, a spring-urged valve seating device having universal contact with the valve, and an adjustable stop member for engaging the valve between the central and marglnal portions.

6. In a device for injecting liquid fuel under pressure into internal combustion engines, a valve casing, a plane valve seat between a central and a surrounding liquid channel, a

surrounding surface in the same plane as said valve seat, an imperforate integral body to cover said surface, said valve seat, and said channels, said integral body comprising a non-elastic disk shaped central portion to act as a valve in engagement with said valve seat, a non-elastic annular circumferential portion to be clamped against said surrounding surface, and an elastic annular portion between i said non-elastic portions to form a connecting name.

KNUT JONAS ELIAS HESSELMAN. 

